Carroting process



Patented Aug. 13, 1940 UNITED STATES --z,z11,34z

PATENT OFFICE CARROTING- PROCESS New York No Drawing Original application December 1,

1937, Serial No. 177,479. Divided and this application June 25, 1940, Serial No. 342,290

ZClaims.

This invention relates to a carroting process, an art of imparting proper felting characteristics to fur fibers. V

This application is a division of my copending application Serial No. 177,479, filed December 1, 1937, which was in turn a continuation-in-part of my copending applications Serial No. 606,525, filed April 20. 1932, and Serial No. 104,706, filed October 8, 1936. The present application is directed particularly to the use of perchloric acid.

One of the objects of thisinvention is to provide a carroting process which will impart one or more of the following characteristics to fur fibers so treatedz-strong mutual adherence in v the resultant iur to make tight felt; fast shrinking and quick starting during the felting process; little or no staining of the fur fibers; no deterioration for substantial periods of storage, in fact improvement during this period; an ability to mix with an unusually large amount of filler in the resultant felt without detracting from the quality of the felt; an ability to take all shades of dyes, both light and dark, without objectionable *undercasts" or mottled effects. Another. object of this invention is to provide a carroting process utilizing a non-toxic and inexpensive carroting solution. Other objects will be in part obvious and in part pointed out hereinafter.

The invention contemplates the utilization of novel combinations of chemical reagents for the treatment of furs as will be illustrativelydescribed herein, and the scope of the invention will be indicated in the followingclaims.

Generally speaking, felt such as that used in hats comprises a compact mass of interlocking 35 fur fibers. For example, in hat manufacture the fibers are deposited loosely upon a cone, and after wetting and hardening they cling together to form a body which may be removed and put through various operations to bring it down to the normal size of a hat. These operations may be generally characterized as shrinking, rubbing and pounding under a variety of conditions and with various types of machines, all to assure a rapid achievement of the proper size and proper.

5 shape. Two of the most important operations are known as starting and "sizing" in the hatting industry. Fur fibers which have quick starting and fast shrinking characteristics are natu- 50 rally desirable in hatmanufacture. Fur fibers in their natural condition on pelts are not suitable for felting. They must be properly processed prior to the felting operation and this process is generally known in the art as car- 55 roting. The carroting process is particularly important in the manufacture of felt for proper felting characteristics are" only obtained thereby regardless of the quality of the fur fibers.

The carroting process usually comprises combing the carroting solution into the fur while still on the pelt. After drying, the fur is cut from the pelt and generally stored for future use in the felting operation.

The desirable carroting solution should have several inherent characteristics and should impart to the fur several qualities to make it commercially desirable. In the first place, the solution should be non-toxic, if possible, to avoid injury not only to the laborers applying the solution during the carroting process but also the laborers working in the felting operation. Naturally it is desirable to have an inexpensive carroting solution thus to reduce the ultimate manufacturing cost of felt. Due to the fact that the fur after carroting must often be stored'for substantial periods of time before use, the car- .roted fur must not deteriorate with time. .After' the felting operation, especially in the batting industry, the fur must be dyed. Y Accordingly, the carroted fur'should be able to takeall shades of dyes without any undesirable undercasting or mottled effects. According to its characteristics, the carrotingsolution materially affects the speed of starting and sizing as referred to above. Naturally-a quick starting and fast sizing feltis desirable in order to speed the felting operation and thus reduce manufacturing costs. The carroting process should impart other characteristics to the fur some of which-will bereferred to hereinafter.

It is now generally recognized that a carroting solution should include a hydrolyzing agent and an oxidizing agent. Just why these ingredients are necessary constituents in a carroting'solution is-not definitely known but successful carroting solutions now in use include these ingredientsin one form or another.

For many years the so-called mercurycarrot" was the accepted standard carroting solution in the batting industry. Mercury carrot compriss mercury nitrate in an excess of nitric acid and it' imparts several very desirable characteristics to the fur fibers. For so carroted improves with age and thus may be stored for substantial periods of time. Mercury carrot also seems to add a substantial amount of weight to the fur and fur so carroted is capable of taking a large amount of filler in the resultant felt. In spite of these advantages the mercury carrot is far from ideal. It has a definitely toxic effect which often seriously impairs the health of the laborers coming in con- 55 tact with fur so carroted. It discolors the fur, making the use of lighter pastel dye shades impossible, and it is expensive.

Because of the shortcomings of the mercury carrot a great deal of effort has been expended in an attempt to devise a non-toxic carrot, preferably non-mercury, due to the above effects of this element. This unusual activity has met with a fair degree of success in some cases and several non-mercury carrots have been devised which can be used with success in limited fields. Significantly, however, most of the fur used in felt manufacture is still carroted with the mercury carrot. In spite of its toxic effect and other disadvantages, it is still considered by many to be usually superior to the non-mercury carrots so far developed.

The principal object of this invention has been to devise a practical and inexpensive carrot retaining in so far as possible all of the advantages of the mercury carrot while eliminating the important disadvantages thereof.

, If the mercury carrot is used in dilute solutions the toxic effect thereof is eliminated for all practical purposes. However, a weak solution of the mercury carrot has not the strength to impart proper felting characteristic to the fur. I have discovered that this deficiency may be eliminated by the addition of two strong oxidlz-' ing agents to a weak mercury carrot solution. To the weak solution of mercury carrot comprising mercury nitrate in an excess of nitric acid, I add strong hydrogen peroxide and any one of several peroxygen compounds. The four peroxygen compounds which I have found workable in this solution are ammonium persulphate, ammonium perchlorate, sodium perchlorate and perchloric acid. Of these I have obtained best results with ammonium persulphate and accordingly my preferred carrot comprises mercury nitrate, nitric acid, ammonium persulphate and strong hydrogen peroxide. Diiferent strengths of hydrogen peroxide may be used ,with varying results but my present experiments indicate a lower limit of 25 volume strength and an upper limit of volume strength although I do not wish to be definitely limited to any particular values. The best values and proportions of the various ingredients comprising this carroting solution cannot be exactly stated without several years research covering a variety of conditions under which the fur is used in felt manufacture. However, good carroting results have been ob tained in the solutions to follow, it being understood that these are merely illustrative examples and may vary widely in accordance with particular conditions and in accordance with the results obtained from an extended period of use:

Example 1 Mercury nitrate .03 molal Nitric acid .09 molal Ammonium persulphate .35 molal Hydrogen peroxide 25 volume strength Example 2 Mercury nitrate .04 molal Nitric acid. .14 molal Sodium perchlorate .44 molal Hydrogen peroxide 45 volume strength Example 3 Mercury nitrate .05 molal Nitric acid .15 molal Ammonium perchlorate .35 molal Hydrogen peroxide 45 volume strength Example 4 Mercury nitrate .05 molal Nitric acid .14 molal Perchloric acid .3 molal Hydrogen peroxide 45 volume strength The above solutions may be applied to the fur by combing before the fur has been removed from the pelts without any danger mainly because of the small amount of mercury nitrate therein. Furthermore, fur so carroted may be used with safety during the felting process without toxic eflects. The ingredients of the above solutions are relatively inexpensive thus reducing materially the cost of the carroting process.

Furthermore, I have found that fur carroted in the above described manner is unstained and thus may take any shade of dye without objectionable undercasts or mottling. The fur may be stored for a substantial period of time and improves with age; the solution also adds considerable weight to the fur in the same manner as previously explained with respect to the mercury carrot. Such fur is also quick starting and fast shrinking, characteristics much to be desired by the hat manufacturer. Further still, this fur is capable of taking a substantial quantity of filler in the felt without deterioration thereof. Briefly, fur carroted with the above solutions retains the many advantages of the mercury carrot without the disadvantages and at a considerable saving in expense.

Accordingly, it will be seen that the several objects hereinabove referred to as well as many others have been successfully and practically accomplished.

As the art herein described may be varied in various parts without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. The hereindescribed art of preparing fur for felting comprising applying to the fur a solution of mercury nitrate containing an excess of nitric acid, hydrogen peroxide, and perchloric acid.

2. The herein described art of preparing fur for felting comprising applying to the fur a solution of mercury nitrate .05 molal, nitric acid .14 molal, perchloric acid .3 molal, and hydrogen peroxide of 45 volume strength.

WARREN C. MERCER. 

